Low-water alarm for



SELAH DUSTIN, OF DETROIT, MICHIGAN.

LOW-WATER ALARM FOR STEAM-BOILERS.

Specification forming part of Letters Patent No. 23,761, dated April 26, 1859; Reissued May 27, 1860, No. 937.

To all 'whom itmay concern:

Be it known that I, SELAH DUsrIN, of De- A troit, in the county of lVayne and State of Michigan, have invented certain new and useful improvements in an apparatus for indicating, by an alarm, the height of the water in a steam-boiler when below or above the pro-per water line or level; and I do hereby declare the following to be a full, clear, and exact description of the construction and operation of the same, reference being had to the accompanying drawings, which represent a section through a steamboiler and through the apparatus referred to.

I am aware that many devices have been invented for ascertaining when the water in a steam boiler is above or below what is termed the water line, and to give an alarm when it so falls and rises. And I am aware that, among these many devices, which are almost invariably arranged on the outside of the boiler, there has been one at least where a steam cylinder or chamber has been used in the inside of the boiler. But among all those of which I have any knowledge there are none that operate without packing, or without the pressure of the steam upon either the rods or cocks, unless t-he steam chamber be outside of the boiler.

It is one of the conditions of my invention that the steam cylinder or chamber shall be inside of the boiler; and the nat-ure and object of my invent-ion is to cause a steam cylinder or chamber so placed inside of a boiler to be opened to, or closed against, the steam therein, by a pair of valves which are in equilibrio, and are raised and lowered by a float on or near the surface of thewater in the boiler, by which means I avoid all pressure against the valves except that derived from the float, and avoidf' also all packed joints, which are so uncertain in their operation.

If a chamber, valve, or cock is operated with the pressure of the steam upon it, which may be l5 pounds to the square inch, or it may be at another time 100 pounds to the square inch, such chamber valve or cock, with the constantly varying pressure upon it cannot always and with certainty indicate the height of water in the boiler. Much less sistance of a packed rod, or joint which is* I,to describe the same with. reference toy the drawings.

A, represents a portion of a boiler, in which the water line may be at B.

C, is a cylinder inside of the boiler which is entirely closed, except the two openings a, a, one in each of its heads b. On these heads may be placed guides c, c, through which a rod CZ, may play, and be kept in a vertical position. This rod d, carries two valves e e the upper one being inside of the cylinder C, and closing upward against the opening a, while the lower one is below the cylinder and closes against the opening c, in the lower head On the lower end of this rod d, there is a ball or float D, that always follows the surface of the water in the boiler.

From the cylinder C, there extends a steam pipe E, which passes out through the crown of the boiler and may have upon its upper and outer end a steam whistle (as shown in red lines) or any other signal to indicate when there is an open steam passage through the cylinder C, and pipe E.

Now it is obvious that however great the pressure may be in the boiler it bears equally over all parts of the cylinder C, as well as its valves e, c, and they will open as easily las they would in a vacuum. When the water gets lower in the boiler than the proper line, the float D follows it, and thus opens the valves e e, which allows the steam to pass out and blow the whistle or sound an alarm. The pumps being started or water furnished to the boiler, the float will rise, and carryy up the valves against the cylinder heads, and thus close the spaces, and stop the issue of steam, and the alarm and thus show that the regular quantity of water is in the boiler. It is obvious that the rod CZ, may, instead of being straight and vertical, be curved or bent in the form of a lever, and still operate the two valvesthe main object being to so arrange the valves inside of the boiler, as that there shall be no pressure against them (practically), and no packed joints, thus causing the slightest deviation of the iioat, or water line below a given point to open said valves.

f, is a collar or stop on the rod d, to prevent the ball or ioat from decending too far below the point that opens the valves. This contrivance indicates, or signals, when the water is too low in the boiler. Now it is obvious that, by simply reversing` the contrivance or turning it upside down it may in the same manner be made to indicate when a suiicient height of water is in the boiler-and one may thus sound the alarm when the supply is insufcient, and the other sound the alarm when the supply is hadand either of these contrivances may be connected with mechanism that will supply the water, or cut olf the supply when the quantity is furnished.

Having thus fully described the nature and object of my invention, and in what particulars it differs from other contrivances for a similar purpose, what I claim therein as new, and desire to secure by Letters Patent is- In combination with a steam cylinder located inside of a steam boiler, and having two openings in it, a float and rod carrying or operating` two valves, in equilibrio, and having no packed oints, substantially as described, by which means I avoid all undue pressure and friction, and render the float more sensitive to any variation of the height of the water in the boiler and thus obtain a more reliable indication, or signal than by any of the heretofore essayed plans, as

set forth.

SELAH DUSTIN.

Witnesses A. B. STOUGHTON, E. COHEN. 

